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Magnesium Sulfate

Magnesium Sulfate

Physical and chemical properties of magnesium sulfate

Magnesium sulfate and medicine


Magnesium sulfate (MgSO4) is a white powder, commonly known as epsom salts. It is easily dissolved in water, making it a source of magnesium that can be readily absorbed by living things. It is used in manufacturing mother of pearl, dyeing calico, n tanning leather, manufacturing fertilizer, and treating and preventing seizures during pregnancy. Magnesium sulfate is also used to treat constipation. It has recently been noticed that many people with diabetes have abnormally low levels of magnesium ions in their blood.

Physical and chemical properties of magnesium sulfate

Magnesium sulfate is obtained from the mineral epsomite, a white solid. It can also be prepared commercially by the reaction of magnesium carbonate (MgCO3) with sulfuric acid (H2SO4). Magnesium sulfate is usually found in the form magnesium sulfate heptahydrate (MgSO47 H2O). The hepta prefix refers to the seven water molecules that are loosely attached to each magnesium sulfate molecule. Magnesium sulfate is very soluble in water. At room temperature about 1.5 pounds (700 g) of MgSO4 can be dissolved in a quart (1 liter) of water.

When dissolved in water, magnesium sulfate ionizes (separates) into magnesium (Mg2+) ions and sulfate (SO42-) ions. Solutions of magnesium sulfate have a neutral pH. Magnesium sulfate is used in many industrial processes and in the manufacturing of fertilizers. Magnesium is essential for plant growth because each chlorophyll molecule contains a magnesium atom. Without this magnesium atom in the center of the chlorophyll molecule, plants would be unable to use the energy from sunlight for growth.

Magnesium sulfate and medicine

Magnesium sulfate is used to prevent the convulsions and seizures that can occur during pregnancy. This condition, known as eclampsia, is characterized by high blood pressure, edema (swelling of tissues, notably in the arms and legs), and convulsions. Magnesium sulfate is used to prevent and reduce the severity of convulsions and to reduce some excess body fluid.

Magnesium sulfate is used as a purgative (laxative). It is thought to work by preventing the intestines from taking up or absorbing water from their contents, thus stimulating more frequent bowel movements. It has also been used to treat some heavy metal (notably barium poisoning, which is in the same family of the periodic table) and works by helping the body to rid itself of the contents of the digestive tract more rapidly. Magnesium sulfate is used to treat conditions of low blood levels of magnesium. It is used over other compounds containing magnesium because of its greater solubility and thus more rapid uptake by the body.


Eclampsia A condition of pregnancy marked by high blood pressure, swelling of body tissues, and eventually, convulsions.

Edema An abnormal collection of fluids in the body tissues.

Recent research has shown that there is a link between diabetes and lower blood levels of magnesium. This does not necessarily mean that low blood levels of magnesium cause diabetes, but may simply mean that magnesium is lost more rapidly due to the frequent urination of people with diabetes.

See also Alkaline earth metals; Diabetes mellitus.



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Magnesium Supplementation in the Treatment of Diabetes. Saturday Evening Post 264 (September-October 1994): 66.

Malesky, G. Magnesium for Moms to Be. Prevention 41 (January 1989): 8.

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Amethyst Galleries: The Mineral Gallery The Mineral Epsomite <> (accessed December 2, 2006).

Louis Gotlib

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